A generic gas generator is disclosed in EP 1 544 060 A1. Upon activation of the igniter, the pyrotechnical propellant in the combustion chamber is burned off and the compressed gas generated thereby will destroy a diaphragm arranged between the combustion chamber and the pressure chamber. This produces an abrupt pressure drop by which a so-called shock wave is generated which abruptly propagates through the pressure chamber to destroy another diaphragm arranged at the end of the pressure chamber remote from the combustion chamber. A mixture of compressed gas and hot gas will then emerge from the associated port. Such hybrid gas generators distinguish themselves by small structural dimensions and rapid escape of the gas, but have rather short gas supply times.
The present invention, by contrast, provides a gas generator and a method of activating a vehicle occupant restraint system in which both a rapid supply of gas immediately upon activation and also a long gas supply time are ensured.